export function addClass(el ,className) {//添加className
    if (hasClass(el,className)) {
        return
    }
    let newClass = el.className.split('')
    newClass.push(className)
    el.className = newClass.join('')
}
export function hasClass(el ,className) {//判断是否有className
    let reg = new RegExp('(^|\\s)'+ className+ '(\\s|$)')
    return reg.test(el.className)

}
export function getData(el,name,val) {
    const prefix = 'data-'
    name = prefix + name
    if(val) {
        return el.setAttribute(name,val)
    }else{
        return el.getAttribute(name)
    }
}